A 59-year-old Bronx school crossing guard became New York’s first murder victim of 2013 today when she and her daughter were shot by her daughter’s boyfriend, law-enforcement sources said.

The boyfriend, identified by sources at Raymond Mayrant, 25, allegedly confronted his girlfriend Diamond Dunn in an apartment in the Monroe Houses project on Story Avenue in The Bronx just before 1 p.m.

“Why’d ya do me like that?” demanded Mayrant of the 22-year-old Dunn, who has a child with him, sources said.

He then allegedly shot Dunn once in the nose — and shot her mother, Elzina “Zina” Brown, at least once in the chest, according to sources. Mayrant then fled.

Brown was on her lunch break from working as a school crossing guard when she was gunned down, according to a neighbor.

Brown was pronounced dead at the scene. In an online personal profile, Elzina wrote that she was born in Brooklyn, had 12 siblings, and also worked as a day-care provider in addition to being a school crossing guard.

Her daughter Dunn was taken to Jacobi Hospital, where she was speaking to police, according to sources. She was expected to survive.

Cops now are hunting for Mayrant, whose most recent residence was in Long Island City, Queens, sources said.

Mayrant has multiple prior arrests, for assault, grand larceny, possession of stolen property and resisting arrest, according to records and sources.

He currently faces larceny charges in Queens, where prosecutors alleged that last October he stole a 2002 Infitiniti during a test drive with its rightful owner, then offered to sell the car back to the owner. He also was arrested last September in Brooklyn for riding a bicycle in a restricted area.

Brown’s brother Robert angrily said “I’m ready to kill the boy. I hope I don’t catch him. “

Robert said that he was told that “Raymond and Diamond got into it. They started fighting and he started shooting.”

Dunn’s other uncle Andre Williams, 54, called Brown “a God-fearing woman who did not have an enemy in the world.”

“When something like this happens it hurts the entire community. We are all so close in these houses, protective of each other,” said Williams, who is a minister. “Its beyond words. This is such a sad start to the New Year.”

He said Brown was a choir director at her church, and that Diamond “works with handicapped people.”

“She’s a beautiful choir girl who could sing her tail off,” Williams said of his niece.

“This breaks my heart. She wasn’t a street person, she was a good. That’s why it hurts so much.”

A neighbor of the Elzina said, “Zina raised her daughter the right way, on the straight and narrow.”

“Her death is a curveball that life has thrown at us. It knocked the wind out of my chest,” the said neighbor, who declined to give their name. “She never said an unkind word to no one. Her mom died of old age and her nephew died of heart attack within the last year. She suffered so much loss in her life.”

Another neighbor said fumed, “There’s gotta be another way to solve problems. The gun violence has to stop.”

“Zina was on her lunch break. She came home to just relax,” the neighbor noted.

That neighbor said Elzina “was loud and made sure the traffic stopped” when working as a crossing guard.

“She took care of those kids. This is a pain everyone in the community will feel.”